U.S. Pat. No. 6,302,391, which is hereby incorporated by reference herein, discloses an apparatus for varying the speed of flat products, wherein a copy is first engaged by high speed conveyor belts. The copy then passes through tension rollers while at the same time is taken over by liner sections of deceleration rollers where a trailing end of the copy leaves the nip between the tension rollers. Downstream of the nip, the high speed conveyor belts gradually diverge; the copy is no longer touched by high speed belts and can be braked by the liner sections, which cover part of the circumference of the deceleration rollers. The release of the copy by the deceleration rollers takes place at the same moment when the leading edge of the copy is engaged by the slow conveyor belts. The slow conveyor belt system is used to transport the copy to the second longitudinal folders. With this type of configuration, the deceleration rollers may be adjusted by moving the support for one of the deceleration rollers to modify the gap between the liner sections. This adjustment of the slow conveyor belt system also adjusts the accessibility to the high speed conveyor belts.